If I drag a whole album to the playlist panel, it seems to randomly mix them up. The songs are in numerical order within the album folder, the files are numbered 01, 02 etc and are also numbered within the tags. Is there something I am missing or have selected? Is there anyway to re-sort them once they are in the playlist?

I don't know what are you exactly drag&droping but i always get a pretty consistent behavior.

If i select an album in the "Section" pane, i sort the songs in the "Track List" pane by title name or track number and drag and drop all the the songs into the "Playlist" pane, they are enqueued in the same order as in the "Track List" pane.

If i double click or right-click and choose "Play" or "Enqueue" an album in the "Section" pane, it gets always get enqueued and ordered by track number, no matter how it's sorted in the "Tracklist" pane (which list the tracks of the currently selected album in the "Section" pane).